Piano.



UNITED STATES PATENT OFFIGE.

ANTON KRIEGHOFF, OF BOSTON, MASSACHUSETTS, ASSIGNOR T0 ANTON KRIEGHOFFCOMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

PIANO.

Specification of Letters Patent.

Patented Sept. 4, 191 '7,

Application filed. September 7, 1915. Serial No. 49,145

To all whom it may concern Be it known that I, ANTON Kinnenorr, acitizen of the United States, residing at Boston, county of Suffolk,State of Massachusetts, have invented an Improvement in Pianos, of whichthe following descriptlon, in connection with the accompanying drawing,is a specification, like characters on the drawing representing likeparts.

This invention relates to a piano sounding board. The novel constructionherein shown is a modification of the improvement in piano string platesand sounding boards and associated parts for which a Datent hasheretofore been applied for by the inventor hereof in application filedMay 13, 1915, Serial No. 27,927. i

In the present construction there is simllarly employed a sounding-boardof the common type but without having the customary bridges positionedthereupon. Herein, the string plate of a piano or similar instrument isprovided with a relatively flexible section which serves primarlly as anauxiliary sounding board and in addition bears the hitch pins for thetreble strings and a bridge for the bass strings. The hitch pins for thebass strlngs are on the rigid metal string plate. This flexible resonantsection may be suitably braced and secured to the usual string plateand, in this embodiment, is integral at one end thereof with the stringplate, while the opposite end of the section is relatively free. Otherobjects of the invention will more fully appear from the followingdescription and the accompanying drawings and will be pointed out in theannexed claims.

Figure 1 is a plan view of the novel piano string plate andsounding-board;

Fig. 2 is a section on the line 22 of Fig. 1;

Fig. 3 is a section on the l1ne 3-3 of Fig. 1;

Fig. 4 is a sectional detail of one of the transmitters.

The drawings herein disclose the invention as embodied in a piano of anuprlght type but, obviously, the invention may equally be embodied withslight changes 1n pianos and similar instruments of different types.

The cast metal string plate 1 has secured thereto the piano soundingboard 2. The string plate is generally of the type at present in use andis suitably braced to withstand the stresses entailed by the tensionedstrings. This string plate has a section 3, thinner than most portionsof the plate 1. The section 8, replacing the usual rigid plate portionbearing the hitch pins, is relatively flexible, and, while it may bemade of any suitable resonant material, it, as shown in this selectedembodiment, is integrally cast with the string plate 1 at one end. Thesection 3, which follows the general direction of the usual line ofhitch pins, is preferably braced at the opposite end portion to thestring plate. And, eX- cept as noted, this section does not come intocontact with the string plate. The vertic'al string plate bars i haveoffset portions 5 which pass behind the section out of 0011- tacttherewith. The section 3, here shown, is made wider than the section inthe struc ture shown in the former application above referred to, inorder to attain greater strength at the free end. The middle portion ofthe section is cut away, leaving the opening 6, which functions tolessen the stiffness of this section 3 at this. point, and to permitgreater flexibility and afiord increased responsiveness of the sectionto vibratory activity imparted thereto by the pulsations which may beset up in a string.

The lower end of the section 3 is braced against the upward pull exertedthereupon by the treble strings, the lower ends of which are secured tothe section. The section at the lower end bears thereupon the lugs 7which are preferably cast integrally with the section. While two suchlugs are shown in the accompanying drawing it is obvious that one ormore may be used and that they may be positioned with relation to thesection 3 and the string plate 1 as appears desirable and consistentwith structural efliciency and section flexibility. In the brace and lugconstruction in this embodiment, the lower ends 8 of the braces 9 areslightly tapered and balled or rounded so that they may have a pivotalyieldable or rocking fit in the sockets 10 formed in the string platelugs 7. The upper ends of the braces 9 are preferably recessed orcupped. These cups 11 of the braces 9 receive therein the rounded endsof set screws 12-. These set screws are received in threaded engagementin apertures 13 in a lug 14, preferably integral with the transversestays 15 of the frame 1. Each set screw 12 through its engagement withthe cupped end of a brace 9 affords a means for retaining the platesection 3 in proper spaced relation to the string plate against the pullexerted on the section by the treble strings. These plate braces 9 aremounted by means of this lug construction so that the braces cannotcontact with the adjacent strings even at the moment of their vibrationsof greatest amplitude. This braced construction thus gives rise to a.structure which provides a section with a relatively floating or freeend. Such a section has increased flexibility and increasedresponsiveness to sound vibrations as compared with applicants earlierflexible section wherein the flexible section was preferably integralwith the string plate at each end. The tapered and cupped constructionof the braces and lugs affords a strengthening medium which effectivelyachieves its function yet does not greatly hinder or deaden thevibratory motion induced in the plate section by the strings as thebraces are afforded a yieldable, non-rigid mounting.

The hitch pins 16 for the treble strings 17 are secured adjacent theupper edge of the flexible section. A rib 18 cast integrally with thesection extends practically its length. This rib provides a bridge forthe strings leading from the hitch pins 16 to the usual upper bearing 19under the pressure bar 20 to the wrest pins 21. These wrest pins 21,following the usual practice, are passed through the string plate 1 andare embedded in the wrest plank. The hitch pins 22 for the bass strings23 are on the plate while a bearing or bridge is preferably provided forsuch strings on the section. As shown in Fig. 1, this bridge consists ofa rib 24 which extends a short distance along the lower edge of thesection. Bearing pins 25 are secured therein and provide a bearing onthe section 3 for the bass strings leading from their hitch pins overthe section to their respective wrest pins 21. The portions of thetreble strings which may be put in vibration by the usual hammers arethose comprehended between the rib 18 of the flexible section and thebearing 19 of the string plate, while similar portions of the bassstrings are between the rib 21 of the section 3 and the bearing 26 ofthe string plate.

The rib 18 may thus receive and directly impart to the flexible section3 the vibrations set up in the treble strings, while the rib 24 maysimilarly function for the vibrations of the bass strings. The section,which as conditions demand may be made more or less flexible andelastic, readily receives and takes up the string vibrations.

The transmitters 27 are provided for the purpose of transmitting to thesounding board the vibratory energy imparted to the flexible section.These transmitters each consist of a post 28, preferably of metal, whichis passed through the section and is received in threaded engagementwith the wooden sounding board. In this embodiment, a block of wood 29is aflixed to the rear face of the sounding board opposite each post andreceives in threaded engagement the post end. The other end of the post,extending through the section, has threaded thereon two nuts 30 whichare adapted to be turned tightly against the front and rear facesrespectively of the flexible section. The sounding board freed from theusual bridges or braces readily responds to the vibrations impartedthereto by the transmitters and may resonantly and freely vibratesubstantially throughout its area.

This invention thus provides a sounding board whose resonance is greatlyaugmented though the elimination of the customary bridges from thesounding board and hence added responsiveness to sound vibrationscommunicated thereto is entailed. Labor and material costs are reducedby this novel construction which is at once durable and of greatersimplicity than the present structures. And, while the embodiment of theinvention is disclosed herein as applied to a piano structure, it willreadily be understood that the principles may be embodied in other formsof stringed instruments whether the' string actuating means bemechanical, electrical or manual.

It is to be understood that the construction disclosed herein isillustrative but not restrictive and that the same may be modifiedwithin the meaning and scope of the claims which follow.

Having thus described my invention what I claim as new, and desire tosecure by Letters Patent, is:

1. In a musical instrument, a string plate, a sounding-board securedthereto, a relatively flexible section fixedly connected at one end onlyto said string plate, strings to produce sound vibrations uponactuation, means for causing the strin vibrations to be communicated tosaid section, and means for communicating to the sounding board thevibrations communicated to said section.

2. In a musical instrument, a string plate, a soundin -board securedthereto, a relatively flexible section integral at one end only withsaid string plate, strings to produce sound vibrations upon actuation,bridges for the strings on said section, and means for connecting saidsection to the sounding board whereby the vibrations set up in thesection are communicated to the sounding-board.

3. In a musical instrument, a string plate, a sounding-board securedthereto, a relatively flexible section fixedly connected at one end onlyto said string plate, means for bracing the opposite end of the flexiblesection, strings to produce sound-vibrations upon actuation, bridges forthe strings upon said section and means for connecting the section tothe sounding-board whereby sound vibrations are communicated from theflexible section to the sounding board.

4. In a musical instrument, a string plate, a sounding-board securedthereto, a substantially diagonally disposed section having one end onlyintegral with the string plate, strings to produce sound vibrations,hitch pins on said section for the treble strings, hitch pins on thestring plate for the bass strings, a bridge on the section for the bassstrings, and means for com- Inunicating the vibrations of the section tothe sounding board.

5. In a musical instrument, a string plate, a sounding-board securedthereto, a relatively flexible section integrally connected at one endonly to the string plate, yieldably mounted means for bracing theopposite end of said section, strings to produce sound vibrations uponactuation, means for causing the string vibrations to be communicated tosaid flexible section and sound posts connecting said section and thesounding-board whereby sound vibrations are communicated from theflexible section to the soundingboard.

6. In a musical instrument, a string plate, a sounding-board securedthereto, a relatively flexible section integrally connected at one endonly to the string plate, yieldably mounted divergent members forbracing the opposite end of the flexible section to the string plate,strings to produce sound vibrations upon actuation, means for causingthe string vibrations to be communicated to the flexible section and aplurality of members connecting said section to the sounding boardwhereby sound vibrations are communicated from the flexible section tothe sounding-board.

7. In a musical instrument, a string plate, a sounding-board securedthereto, a relatively flexible section integral at one end only with thestring plate and having its other portions free therefrom, adjustablemeans for bracing the opposite end of said flexible section, saidbracing means having substantially ball and socket mountings, meanswhereby the string vibrations are communicated to the flexible sectionand means for communicating the section vibrations to the soundingboard.

8. In a musical instrument, a string plate, a sounding-boardsecuredthereto, strings,

an elongated, relatively flexible section integral at one end only withthe string plate, said section being longitudinally apertured toincrease its flexibility, means for communicating string vibrations tothe section, and means for communicating to the soundingboard thevibrations communicated to the section.

In testimony whereof, I have signed my name to this specification.

ANTON KRIEGHOFF.

copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. G.

